Contact

Taste receptors are unique sensory cells sharing epithelial and neuronal features that transduce distinct chemical stimuli into neural signals to mediate the sense of taste. Taste perception in newborn mammals is essential to distinguish nutritional from toxic substances to sustain growth and development. I am interested in the molecular cues necessary for establishing the taste progenitors and regulating their differentiation and in addressing the fundamental mechanisms and differential regulation of anterior and posterior taste fields.
I address these specific questions using mouse as an experimental model system making use of molecular genetic approaches. In mammals the taste receptor cells are organized within epithelial mesenchymal specializations called papillae. Through a series of morphogenetic events the homogenous early lingual epithelium transform into taste bearing (the placodes) and non-taste fields. The placodes with the underlying mesenchyme forms a papilla and the functional taste receptor cells form at the apices of the papilla at the end of gestation. Our lineage tracing studies using inducible tissue specific genetic mouse models showed that the initially formed taste placodes that express the key signaling molecule Sonic hedgehog (Shh) are the taste progenitor population that give rise to adult taste cells, and not to the papillae that house these receptor cells (Thirumangalathu et al 2009). Current research effort focuses to identify the temporal and spatial requirements of Shh with respect to taste cell differentiation and papilla morphogenesis using conditional inducible genetic tools combined with dynamic live imaging.

Shh descendent cells stained with β-gal (red) and the pan neuronal marker PGP9.5 (green) at E15.5 from embryos induced for cre recombination at E13.5 shows placodal descendent cells at the apices of the papilla in the taste cell bearing region that are well innervated.

Our lineage tracing studies establishing Shh descendent taste placodes as embryonic progenitor population has been a major step in allowing us to explore the role of signaling molecules with respect to its function within taste progenitor population. As Wnt/β-catenin signaling is active within the taste epithelium during embryonic development (Liu et al 2007), we are continuing with our conditional molecular genetic approaches to temporally and spatially dissect the function(s) of Wnt/β-catenin within Shh expressing taste progenitor population and its impact on papillary morphogenesis. These studies would reveal shared and unique properties of taste cell development with those of neuronal and epithelial appendage or novel features in the molecular regulation of this important sensory system. Further, insights gained from developmental pathways affecting the genesis of taste receptor cells will advance our understanding of mature adult taste system function and its role in taste mediated food choices.